Integrated hydrogeological and geophysical study of depression‐focused groundwater recharge in the Canadian prairies
Integrated hydrogeological and geophysical study of depression‐focused groundwater recharge in the Canadian prairies
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加拿大大草原洼地地下水补给的综合水文地质和地球物理研究
DOI：
10.1029/2003wr002982
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发表时间：
2004
影响因子：
5.4
通讯作者：
M. Hayashi
中科院分区：
文献类型：
--
作者：
S. Berthold;L. Bentley;M. Hayashi
在北美北部草原地区，由于融雪水被困在小的地形凹地中，形成了无数的季节性湿地和短暂的池塘。在加拿大萨斯喀彻温省圣丹尼斯国家野生动物区，一项详细的水文地质调查与电阻率成像(ERI)相结合，以评估湿地和池塘在凹陷地下水补给中的作用。对地下水样品的分析表明有两个明显的地球化学区：109湿地下的盐淋失区和邻近旱地下的盐积累区。两个中间带被确定为部分淋滤或混合淋滤-未淋滤和前现代或混合的盐水-非咸水。利用ERI计算的电导率(EC)与地下水EC的相关性，对109附近地区的电阻率图像进行了分类。ERI数据清楚地表明，无论规模大小，所有凹陷都会发生聚焦于凹陷的补给。淋溶作用被观察到区域间歇含水层的深度，表明集中于凹陷的补给对区域地下水系统有贡献。ERI数据还揭示了仅靠水文地质观测无法识别的复杂的盐分分布模式。盐分的复杂分布似乎是由湿地之间的相互作用和地形变化造成的。
In the northern prairie region of North America, numerous seasonal wetlands and ephemeral ponds form as snowmelt water is trapped in small topographical depressions. A detailed hydrogeological investigation is combined with electrical resistivity imaging (ERI) to evaluate the roles of the wetlands and ponds on depression‐focused groundwater recharge at the St. Denis National Wildlife Area in Saskatchewan, Canada. The analysis of groundwater samples indicated two distinct geochemical zones: a zone of salt leaching under Wetland 109 and zones of salt accumulation under the adjacent uplands. Two intermediate zones were identified as partially leached or mixed leached‐unleached and premodern or mixed saline‐nonsaline water. The resistivity images of the areas around 109 were classified using the correlation between ERI‐derived electrical conductivity (EC) and the groundwater EC. The ERI data clearly showed that depression‐focused recharge occurs under all depressions regardless of size. Leaching is observed to the depth of a regional intertill aquifer, indicating that depression‐focused recharge contributes to the regional groundwater system. The ERI data also revealed the complex pattern of salt distribution that could not have been recognized by hydrogeological observations alone. The complex distribution of salts appears to be caused by interaction between wetlands and variations in topography.